Q In pregnant working women, does physical exertion at work (standing, lifting, night work, and long hours) increase the risk
of preterm delivery or fetal growth restriction?

METHODS

Design:

prospective cohort study.

Setting:

prenatal clinics at 3 hospitals in North Carolina, USA.

Participants:

1908 English speaking women ⩾16 years of age who were 24–29 weeks pregnant with a singleton gestation and had worked ⩾28 days
in the first 2 trimesters of pregnancy.

Risk factors:

physical exertion at work during the first or second trimester, including standing, heavy lifting (>11 kg), regular night
work (10 pm to 7 am), and long hours (exposure determined by telephone interview at 24–31 wks gestation).